Update bower.json for Polymer elements and add PRESUBMIT.py

third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-behavior.html

Index: third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-behavior.html
diff --git a/third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-behavior.html b/third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-behavior.html
index 227fb4dbaef5274f510dfb5385d4d86b49f6c8ec..0afcb8b7f82da317e901295aa392c7f80d95fd3c 100644
--- a/third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-behavior.html
+++ b/third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-behavior.html
@@ -52,7 +52,7 @@ Custom property | Description | Default
 ### Accessibility
 
 This element has `role="dialog"` by default. Depending on the context, it may be more appropriate
-to override this attribute with `role="alertdialog"`. The header (a `<h2>` element) will
+to override this attribute with `role="alertdialog"`.
 
 If `modal` is set, the element will set `aria-modal` and prevent the focus from exiting the element.
 It will also ensure that focus remains in the dialog.
@@ -173,15 +173,17 @@ The `aria-labelledby` attribute will be set to the header element, if one exists
 
     _onDialogClick: function(event) {
       var target = event.target;
-      while (target !== this) {
-        if (target.hasAttribute('dialog-dismiss')) {
-          this._updateClosingReasonConfirmed(false);
-          this.close();
-          break;
-        } else if (target.hasAttribute('dialog-confirm')) {
-          this._updateClosingReasonConfirmed(true);
-          this.close();
-          break;
+      while (target && target !== this) {
+        if (target.hasAttribute) {
+          if (target.hasAttribute('dialog-dismiss')) {
+            this._updateClosingReasonConfirmed(false);
+            this.close();
+            break;
+          } else if (target.hasAttribute('dialog-confirm')) {
+            this._updateClosingReasonConfirmed(true);
+            this.close();
+            break;
+          }
         }
         target = target.parentNode;
       }